1. Field of Invention
The present invention relates generally to automotive fuel tank filler tubes, more specifically to a restrictor assembly therefore.
2. Description of the Prior Art
With the introduction of catalyst convertors for treating the exhaust gases of internal combustion engines, federal standards were proclomated which were intended to inhibit the filling of fuel tanks of automobiles equipped with such converters with leaded fuel. This was because leaded fuel renders the catalytic converters permanently ineffective. Among the standards is one limiting the amount of leaded fuel that could be delivered to the tank of a converter-equipped automobile to 700 cubic centimeters of fuel be for an automatic shut-off mechanism of a filling nozzle actuates to block flow. Another companion standard provides that the tubular nozzles for unleaded fuel shall not exceed 0.85 inch in diameter and the nozzles for leaded fuel shall not be less than 0.93 inch in diameter.
One industry response to these standards has been to install inlet restrictor assemblies in the fuel filler tube including a spring-loaded movable door normally closing an inlet aperture sized to permit insertion of only an unleaded nozzle for opening the door. U.S. Pat. No. 4,034,784 and U.S. Pat. No. 4,185,844 and U.S. Pat. No. 4,248,279 are relevant to this subject. These patents are assigned to the assignee of the present invention and are exemplary of such assemblies.
In particular, the U.S. Pat. No. 4,248,279 discloses a restrictor inlet with a correctly sized aperture for insertion of only a non-leaded fuel nozzle. To prevent drilling or reaming the aperture for insertion of a larger nozzle, the patent discloses the use of a hardened metal ring in association with the aperture forming portions of the assembly to prevent this enlarging of the opening. It has been found that the hardened metal ring is very effective in preventing enlargement of the aperture.
The present application also utilizes a hard metal member to prevent enlargement of the aperture by drilling or reaming. In addition, the subject improved assembly utilizes a hardened metal reinforcing wall which in addition to the aperture forming portion includes portions extending to opposite sides of the filler tube wall. The reinforced hardened metal wall member of the filler assembly prevents destruction of the aperture forming portions of the assembly by insertion of a pry bar or the like into the aperture and subsequent back and forth working of the assembly which can result in breakage of the end portion forming the aperture. It is desirable that the end portion of the filler assembly be resistant to damage and resultant removal by prying with a bar or like tool.